Evaluation of Xenia and Metaxenia in Pistachio (Pistacia vera L.) Following Pollination with Different Pollen Sources

Pistachio is a dioecious and cross-pollination species and suitable male genotypes is essential for its adequate fruit production. The quality of the produced nuts is also directly affected by pollen sources. In the present study, the female pistachio trees of Akbari commercial cultivar, in their ON-year cycle, were selected and hand-pollinated with three different pollen sources (T5, T17, T18) and compared to open-pollinated trees (T0). This research was undertaken as a completely randomized block design with three replications. Artificial pollination had a positive effect on the fruit set percentage. Furthermore, fruit fresh and dry weights, fruit dimensions, nut as well as kernel characteristics were affected corresponding to each pollen source. Though all 3 pollen sources had a positive effect on measured fruit characteristics, the effect of T17 was more prominent. Owing to xenia and metaxenia effects, longer nuts were observed following pollination with T5 pollen grains. Also, utilization of T17 pollen grains led to production of weightier fruits with higher splitting rate (93.33 % as compared to control, open pollinated trees (63.78%)). The results of the present study approved the imperative role of pollen source for pistachio fruit production. The results also recommended T17 genotype as a suitable pollinizer for Akbari pistachio cultivar.